I'm an employee at PriceSpy (though I'm not writing in an official capacity).
We have some sort of marketing deal with a partner that includes visibility in the Opera browser (my best guess - based on the problem - is that this would be some sort of default speed dial page selection on initial install).
You do not have to be afraid of malware on your computer, it's just the Opera browser doing this
We've gotten complaints directed at us as well, and I've run this up the ladder too se if we want to end this deal.
I agree that the way it's working seems to be either intrusive or malfunctioning ...